The present invention relates generally to electrical circuits, and more specifically, to the simulation of electrostatic discharge.
A modern integrated circuit may communicate by utilizing a number of different input and output signal standards. For example, an integrated circuit may transmit and receive information via one or more input/output circuits, which may be within the same input/output bank, at high speeds (e.g. 1 Gpbs). The input/output circuit typically must also be designed to be protected from (e.g., have a certain immunity to damage from) electrostatic discharge.
In general, an input/output circuit design may be very complex and involve difficult compromises between performance (e.g., speed or data rate) and electrostatic discharge (ESD) protection. For example, a typical input/output circuit design process may involve adding standard, pre-approved ESD protection devices to the input/output circuit. The ESD protection device and the input/output circuit, for example, would then be implemented in silicon and tested to determine if the circuit meets design specifications.
After testing, it may be determined that the selected ESD protection device was not optimum for the desired application, such as for example being too large or in an incorrect configuration, and the process would have to be repeated such as by selecting another ESD protection device or reconfiguring the current design for further testing. In general, this approach is time consuming and expensive with results that are often difficult to predict.
Simulation of circuits may assist in designing circuits with ESD or other protection devices by predicting behavior of such circuits. However, contemporary simulations may run for long periods of time, providing little or no information to the Design Engineer until the simulations are complete and then require a manual interpretation of the simulation results to identify critical parameters and/or critical paths. After analyzing the results, the Design Engineer may then go back to the design and make changes based on feedback from the results, though results traditionally only provide worst case scenarios and the Design Engineer has little insight as to where the next problem or critical area in the design may lie.
Therefore there is a need in the art to improve upon simulation as a predictor for performance of a circuit.